Direct viewing through an eyepiece
When looking through an eyepiece, there is an apparent field of view. This answer says:
Because I was lazy, I used the default telescopes and eyepieces.
which means that the circles shown are what one would see if one had an eyepiece with a field of view equal to the default eyepiece used in the Stellarium simulation. If your eyepieces have a narrower apparent FOV then the circle should be drawn smaller.
The actual FOV is the apparent FOV divided by the magnification.
SO if you have f=1000 mm and a 10 mm eyepiece you have 100x magnification. If your actual eyepiece has an apparent FOV of 50 degrees then your actual FOV is 0.5 degrees or 30 arc minutes.
Just recently they have become closer than that so from now until the end of December you would be able to see them with the eyepiece I've just described.
Your milage may vary
Using your camera
The FOV of your camera's sensor is a totally different issue!
It is rectangular not circular, and so you may have to rotate your camera body around the axis of the telescope to get the long direction or the diagonal direction parallel to the line between the two planets.
Your camera's documentation will give you the CCD sensor's dimensions in millimeters.
Let's say it's h x w = 4mm x 6mm. Assuming there are no lenses in between and your Newtonian telescope's primary mirror's focus is directly on the sensor, the FOV of your sensor is h/f x w/f or 4/1000 x 6/1000 radians. Multiply by $180 / \pi$ to get degrees, so it will be 0.23 x 0.34 degrees, a lot smaller than for an eyepiece!
Diagonally it's $\sqrt{(w/f)^2 + (h/f)^2}$ or 0.41 degrees.
Since your sensor will be a different size:
Your milage may vary